drivers/rtc/rtc-ds1307.c

   1 /*
   2  * rtc-ds1307.c - RTC driver for some mostly-compatible I2C chips.
   3  *
   4  *  Copyright (C) 2005 James Chapman (ds1337 core)
   5  *  Copyright (C) 2006 David Brownell
   6  *  Copyright (C) 2009 Matthias Fuchs (rx8025 support)
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/init.h>
  15 #include <linux/slab.h>
  16 #include <linux/i2c.h>
  17 #include <linux/string.h>
  18 #include <linux/rtc.h>
  19 #include <linux/bcd.h>
  20 #include <linux/rtc/ds1307.h>
  21
  22 /*
  23  * We can't determine type by probing, but if we expect pre-Linux code
  24  * to have set the chip up as a clock (turning on the oscillator and
  25  * setting the date and time), Linux can ignore the non-clock features.
  26  * That's a natural job for a factory or repair bench.
  27  */
  28 enum ds_type {
  29         ds_1307,
  30         ds_1337,
  31         ds_1338,
  32         ds_1339,
  33         ds_1340,
  34         ds_1388,
  35         ds_3231,
  36         m41t00,
  37         mcp7941x,
  38         rx_8025,
  39         last_ds_type /* always last */
  40         /* rs5c372 too?  different address... */
  41 };
  42
  43
  44 /* RTC registers don't differ much, except for the century flag */
  45 #define DS1307_REG_SECS         0x00    /* 00-59 */
  46 #       define DS1307_BIT_CH            0x80
  47 #       define DS1340_BIT_nEOSC         0x80
  48 #       define MCP7941X_BIT_ST          0x80
  49 #define DS1307_REG_MIN          0x01    /* 00-59 */
  50 #define DS1307_REG_HOUR         0x02    /* 00-23, or 1-12{am,pm} */
  51 #       define DS1307_BIT_12HR          0x40    /* in REG_HOUR */
  52 #       define DS1307_BIT_PM            0x20    /* in REG_HOUR */
  53 #       define DS1340_BIT_CENTURY_EN    0x80    /* in REG_HOUR */
  54 #       define DS1340_BIT_CENTURY       0x40    /* in REG_HOUR */
  55 #define DS1307_REG_WDAY         0x03    /* 01-07 */
  56 #       define MCP7941X_BIT_VBATEN      0x08
  57 #define DS1307_REG_MDAY         0x04    /* 01-31 */
  58 #define DS1307_REG_MONTH        0x05    /* 01-12 */
  59 #       define DS1337_BIT_CENTURY       0x80    /* in REG_MONTH */
  60 #define DS1307_REG_YEAR         0x06    /* 00-99 */
  61
  62 /*
  63  * Other registers (control, status, alarms, trickle charge, NVRAM, etc)
  64  * start at 7, and they differ a LOT. Only control and status matter for
  65  * basic RTC date and time functionality; be careful using them.
  66  */
  67 #define DS1307_REG_CONTROL      0x07            /* or ds1338 */
  68 #       define DS1307_BIT_OUT           0x80
  69 #       define DS1338_BIT_OSF           0x20
  70 #       define DS1307_BIT_SQWE          0x10
  71 #       define DS1307_BIT_RS1           0x02
  72 #       define DS1307_BIT_RS0           0x01
  73 #define DS1337_REG_CONTROL      0x0e
  74 #       define DS1337_BIT_nEOSC         0x80
  75 #       define DS1339_BIT_BBSQI         0x20
  76 #       define DS3231_BIT_BBSQW         0x40 /* same as BBSQI */
  77 #       define DS1337_BIT_RS2           0x10
  78 #       define DS1337_BIT_RS1           0x08
  79 #       define DS1337_BIT_INTCN         0x04
  80 #       define DS1337_BIT_A2IE          0x02
  81 #       define DS1337_BIT_A1IE          0x01
  82 #define DS1340_REG_CONTROL      0x07
  83 #       define DS1340_BIT_OUT           0x80
  84 #       define DS1340_BIT_FT            0x40
  85 #       define DS1340_BIT_CALIB_SIGN    0x20
  86 #       define DS1340_M_CALIBRATION     0x1f
  87 #define DS1340_REG_FLAG         0x09
  88 #       define DS1340_BIT_OSF           0x80
  89 #define DS1337_REG_STATUS       0x0f
  90 #       define DS1337_BIT_OSF           0x80
  91 #       define DS1337_BIT_A2I           0x02
  92 #       define DS1337_BIT_A1I           0x01
  93 #define DS1339_REG_ALARM1_SECS  0x07
  94
  95 #define DS13XX_TRICKLE_CHARGER_MAGIC    0xa0
  96
  97 #define RX8025_REG_CTRL1        0x0e
  98 #       define RX8025_BIT_2412          0x20
  99 #define RX8025_REG_CTRL2        0x0f
 100 #       define RX8025_BIT_PON           0x10
 101 #       define RX8025_BIT_VDET          0x40
 102 #       define RX8025_BIT_XST           0x20
 103
 104
 105 struct ds1307 {
 106         u8                      offset; /* register's offset */
 107         u8                      regs[11];
 108         u16                     nvram_offset;
 109         struct bin_attribute    *nvram;
 110         enum ds_type            type;
 111         unsigned long           flags;
 112 #define HAS_NVRAM       0               /* bit 0 == sysfs file active */
 113 #define HAS_ALARM       1               /* bit 1 == irq claimed */
 114         struct i2c_client       *client;
 115         struct rtc_device       *rtc;
 116         struct work_struct      work;
 117         s32 (*read_block_data)(const struct i2c_client *client, u8 command,
 118                                u8 length, u8 *values);
 119         s32 (*write_block_data)(const struct i2c_client *client, u8 command,
 120                                 u8 length, const u8 *values);
 121 };
 122
 123 struct chip_desc {
 124         unsigned                alarm:1;
 125         u16                     nvram_offset;
 126         u16                     nvram_size;
 127         u16                     trickle_charger_reg;
 128 };
 129
 130 static const struct chip_desc chips[last_ds_type] = {
 131         [ds_1307] = {
 132                 .nvram_offset   = 8,
 133                 .nvram_size     = 56,
 134         },
 135         [ds_1337] = {
 136                 .alarm          = 1,
 137         },
 138         [ds_1338] = {
 139                 .nvram_offset   = 8,
 140                 .nvram_size     = 56,
 141         },
 142         [ds_1339] = {
 143                 .alarm          = 1,
 144                 .trickle_charger_reg = 0x10,
 145         },
 146         [ds_1340] = {
 147                 .trickle_charger_reg = 0x08,
 148         },
 149         [ds_1388] = {
 150                 .trickle_charger_reg = 0x0a,
 151         },
 152         [ds_3231] = {
 153                 .alarm          = 1,
 154         },
 155         [mcp7941x] = {
 156                 /* this is battery backed SRAM */
 157                 .nvram_offset   = 0x20,
 158                 .nvram_size     = 0x40,
 159         },
 160 };
 161
 162 static const struct i2c_device_id ds1307_id[] = {
 163         { "ds1307", ds_1307 },
 164         { "ds1337", ds_1337 },
 165         { "ds1338", ds_1338 },
 166         { "ds1339", ds_1339 },
 167         { "ds1388", ds_1388 },
 168         { "ds1340", ds_1340 },
 169         { "ds3231", ds_3231 },
 170         { "m41t00", m41t00 },
 171         { "mcp7941x", mcp7941x },
 172         { "pt7c4338", ds_1307 },
 173         { "rx8025", rx_8025 },
 174         { }
 175 };
 176 MODULE_DEVICE_TABLE(i2c, ds1307_id);
 177
 178 /*----------------------------------------------------------------------*/
 179
 180 #define BLOCK_DATA_MAX_TRIES 10
 181
 182 static s32 ds1307_read_block_data_once(const struct i2c_client *client,
 183                                        u8 command, u8 length, u8 *values)
 184 {
 185         s32 i, data;
 186
 187         for (i = 0; i < length; i++) {
 188                 data = i2c_smbus_read_byte_data(client, command + i);
 189                 if (data < 0)
 190                         return data;
 191                 values[i] = data;
 192         }
 193         return i;
 194 }
 195
 196 static s32 ds1307_read_block_data(const struct i2c_client *client, u8 command,
 197                                   u8 length, u8 *values)
 198 {
 199         u8 oldvalues[I2C_SMBUS_BLOCK_MAX];
 200         s32 ret;
 201         int tries = 0;
 202
 203         dev_dbg(&client->dev, "ds1307_read_block_data (length=%d)\n", length);
 204         ret = ds1307_read_block_data_once(client, command, length, values);
 205         if (ret < 0)
 206                 return ret;
 207         do {
 208                 if (++tries > BLOCK_DATA_MAX_TRIES) {
 209                         dev_err(&client->dev,
 210                                 "ds1307_read_block_data failed\n");
 211                         return -EIO;
 212                 }
 213                 memcpy(oldvalues, values, length);
 214                 ret = ds1307_read_block_data_once(client, command, length,
 215                                                   values);
 216                 if (ret < 0)
 217                         return ret;
 218         } while (memcmp(oldvalues, values, length));
 219         return length;
 220 }
 221
 222 static s32 ds1307_write_block_data(const struct i2c_client *client, u8 command,
 223                                    u8 length, const u8 *values)
 224 {
 225         u8 currvalues[I2C_SMBUS_BLOCK_MAX];
 226         int tries = 0;
 227
 228         dev_dbg(&client->dev, "ds1307_write_block_data (length=%d)\n", length);
 229         do {
 230                 s32 i, ret;
 231
 232                 if (++tries > BLOCK_DATA_MAX_TRIES) {
 233                         dev_err(&client->dev,
 234                                 "ds1307_write_block_data failed\n");
 235                         return -EIO;
 236                 }
 237                 for (i = 0; i < length; i++) {
 238                         ret = i2c_smbus_write_byte_data(client, command + i,
 239                                                         values[i]);
 240                         if (ret < 0)
 241                                 return ret;
 242                 }
 243                 ret = ds1307_read_block_data_once(client, command, length,
 244                                                   currvalues);
 245                 if (ret < 0)
 246                         return ret;
 247         } while (memcmp(currvalues, values, length));
 248         return length;
 249 }
 250
 251 /*----------------------------------------------------------------------*/
 252
 253 /*
 254  * The IRQ logic includes a "real" handler running in IRQ context just
 255  * long enough to schedule this workqueue entry.   We need a task context
 256  * to talk to the RTC, since I2C I/O calls require that; and disable the
 257  * IRQ until we clear its status on the chip, so that this handler can
 258  * work with any type of triggering (not just falling edge).
 259  *
 260  * The ds1337 and ds1339 both have two alarms, but we only use the first
 261  * one (with a "seconds" field).  For ds1337 we expect nINTA is our alarm
 262  * signal; ds1339 chips have only one alarm signal.
 263  */
 264 static void ds1307_work(struct work_struct *work)
 265 {
 266         struct ds1307           *ds1307;
 267         struct i2c_client       *client;
 268         struct mutex            *lock;
 269         int                     stat, control;
 270
 271         ds1307 = container_of(work, struct ds1307, work);
 272         client = ds1307->client;
 273         lock = &ds1307->rtc->ops_lock;
 274
 275         mutex_lock(lock);
 276         stat = i2c_smbus_read_byte_data(client, DS1337_REG_STATUS);
 277         if (stat < 0)
 278                 goto out;
 279
 280         if (stat & DS1337_BIT_A1I) {
 281                 stat &= ~DS1337_BIT_A1I;
 282                 i2c_smbus_write_byte_data(client, DS1337_REG_STATUS, stat);
 283
 284                 control = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
 285                 if (control < 0)
 286                         goto out;
 287
 288                 control &= ~DS1337_BIT_A1IE;
 289                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, control);
 290
 291                 rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
 292         }
 293
 294 out:
 295         if (test_bit(HAS_ALARM, &ds1307->flags))
 296                 enable_irq(client->irq);
 297         mutex_unlock(lock);
 298 }
 299
 300 static irqreturn_t ds1307_irq(int irq, void *dev_id)
 301 {
 302         struct i2c_client       *client = dev_id;
 303         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 304
 305         disable_irq_nosync(irq);
 306         schedule_work(&ds1307->work);
 307         return IRQ_HANDLED;
 308 }
 309
 310 /*----------------------------------------------------------------------*/
 311
 312 static int ds1307_get_time(struct device *dev, struct rtc_time *t)
 313 {
 314         struct ds1307   *ds1307 = dev_get_drvdata(dev);
 315         int             tmp;
 316
 317         /* read the RTC date and time registers all at once */
 318         tmp = ds1307->read_block_data(ds1307->client,
 319                 ds1307->offset, 7, ds1307->regs);
 320         if (tmp != 7) {
 321                 dev_err(dev, "%s error %d\n", "read", tmp);
 322                 return -EIO;
 323         }
 324
 325         dev_dbg(dev, "%s: %7ph\n", "read", ds1307->regs);
 326
 327         t->tm_sec = bcd2bin(ds1307->regs[DS1307_REG_SECS] & 0x7f);
 328         t->tm_min = bcd2bin(ds1307->regs[DS1307_REG_MIN] & 0x7f);
 329         tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
 330         t->tm_hour = bcd2bin(tmp);
 331         t->tm_wday = bcd2bin(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
 332         t->tm_mday = bcd2bin(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
 333         tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
 334         t->tm_mon = bcd2bin(tmp) - 1;
 335
 336         /* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
 337         t->tm_year = bcd2bin(ds1307->regs[DS1307_REG_YEAR]) + 100;
 338
 339         dev_dbg(dev, "%s secs=%d, mins=%d, "
 340                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 341                 "read", t->tm_sec, t->tm_min,
 342                 t->tm_hour, t->tm_mday,
 343                 t->tm_mon, t->tm_year, t->tm_wday);
 344
 345         /* initial clock setting can be undefined */
 346         return rtc_valid_tm(t);
 347 }
 348
 349 static int ds1307_set_time(struct device *dev, struct rtc_time *t)
 350 {
 351         struct ds1307   *ds1307 = dev_get_drvdata(dev);
 352         int             result;
 353         int             tmp;
 354         u8              *buf = ds1307->regs;
 355
 356         dev_dbg(dev, "%s secs=%d, mins=%d, "
 357                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 358                 "write", t->tm_sec, t->tm_min,
 359                 t->tm_hour, t->tm_mday,
 360                 t->tm_mon, t->tm_year, t->tm_wday);
 361
 362         buf[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
 363         buf[DS1307_REG_MIN] = bin2bcd(t->tm_min);
 364         buf[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
 365         buf[DS1307_REG_WDAY] = bin2bcd(t->tm_wday + 1);
 366         buf[DS1307_REG_MDAY] = bin2bcd(t->tm_mday);
 367         buf[DS1307_REG_MONTH] = bin2bcd(t->tm_mon + 1);
 368
 369         /* assume 20YY not 19YY */
 370         tmp = t->tm_year - 100;
 371         buf[DS1307_REG_YEAR] = bin2bcd(tmp);
 372
 373         switch (ds1307->type) {
 374         case ds_1337:
 375         case ds_1339:
 376         case ds_3231:
 377                 buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
 378                 break;
 379         case ds_1340:
 380                 buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
 381                                 | DS1340_BIT_CENTURY;
 382                 break;
 383         case mcp7941x:
 384                 /*
 385                  * these bits were cleared when preparing the date/time
 386                  * values and need to be set again before writing the
 387                  * buffer out to the device.
 388                  */
 389                 buf[DS1307_REG_SECS] |= MCP7941X_BIT_ST;
 390                 buf[DS1307_REG_WDAY] |= MCP7941X_BIT_VBATEN;
 391                 break;
 392         default:
 393                 break;
 394         }
 395
 396         dev_dbg(dev, "%s: %7ph\n", "write", buf);
 397
 398         result = ds1307->write_block_data(ds1307->client,
 399                 ds1307->offset, 7, buf);
 400         if (result < 0) {
 401                 dev_err(dev, "%s error %d\n", "write", result);
 402                 return result;
 403         }
 404         return 0;
 405 }
 406
 407 static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 408 {
 409         struct i2c_client       *client = to_i2c_client(dev);
 410         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 411         int                     ret;
 412
 413         if (!test_bit(HAS_ALARM, &ds1307->flags))
 414                 return -EINVAL;
 415
 416         /* read all ALARM1, ALARM2, and status registers at once */
 417         ret = ds1307->read_block_data(client,
 418                         DS1339_REG_ALARM1_SECS, 9, ds1307->regs);
 419         if (ret != 9) {
 420                 dev_err(dev, "%s error %d\n", "alarm read", ret);
 421                 return -EIO;
 422         }
 423
 424         dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
 425                         "alarm read",
 426                         ds1307->regs[0], ds1307->regs[1],
 427                         ds1307->regs[2], ds1307->regs[3],
 428                         ds1307->regs[4], ds1307->regs[5],
 429                         ds1307->regs[6], ds1307->regs[7],
 430                         ds1307->regs[8]);
 431
 432         /*
 433          * report alarm time (ALARM1); assume 24 hour and day-of-month modes,
 434          * and that all four fields are checked matches
 435          */
 436         t->time.tm_sec = bcd2bin(ds1307->regs[0] & 0x7f);
 437         t->time.tm_min = bcd2bin(ds1307->regs[1] & 0x7f);
 438         t->time.tm_hour = bcd2bin(ds1307->regs[2] & 0x3f);
 439         t->time.tm_mday = bcd2bin(ds1307->regs[3] & 0x3f);
 440         t->time.tm_mon = -1;
 441         t->time.tm_year = -1;
 442         t->time.tm_wday = -1;
 443         t->time.tm_yday = -1;
 444         t->time.tm_isdst = -1;
 445
 446         /* ... and status */
 447         t->enabled = !!(ds1307->regs[7] & DS1337_BIT_A1IE);
 448         t->pending = !!(ds1307->regs[8] & DS1337_BIT_A1I);
 449
 450         dev_dbg(dev, "%s secs=%d, mins=%d, "
 451                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
 452                 "alarm read", t->time.tm_sec, t->time.tm_min,
 453                 t->time.tm_hour, t->time.tm_mday,
 454                 t->enabled, t->pending);
 455
 456         return 0;
 457 }
 458
 459 static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 460 {
 461         struct i2c_client       *client = to_i2c_client(dev);
 462         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 463         unsigned char           *buf = ds1307->regs;
 464         u8                      control, status;
 465         int                     ret;
 466
 467         if (!test_bit(HAS_ALARM, &ds1307->flags))
 468                 return -EINVAL;
 469
 470         dev_dbg(dev, "%s secs=%d, mins=%d, "
 471                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
 472                 "alarm set", t->time.tm_sec, t->time.tm_min,
 473                 t->time.tm_hour, t->time.tm_mday,
 474                 t->enabled, t->pending);
 475
 476         /* read current status of both alarms and the chip */
 477         ret = ds1307->read_block_data(client,
 478                         DS1339_REG_ALARM1_SECS, 9, buf);
 479         if (ret != 9) {
 480                 dev_err(dev, "%s error %d\n", "alarm write", ret);
 481                 return -EIO;
 482         }
 483         control = ds1307->regs[7];
 484         status = ds1307->regs[8];
 485
 486         dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
 487                         "alarm set (old status)",
 488                         ds1307->regs[0], ds1307->regs[1],
 489                         ds1307->regs[2], ds1307->regs[3],
 490                         ds1307->regs[4], ds1307->regs[5],
 491                         ds1307->regs[6], control, status);
 492
 493         /* set ALARM1, using 24 hour and day-of-month modes */
 494         buf[0] = bin2bcd(t->time.tm_sec);
 495         buf[1] = bin2bcd(t->time.tm_min);
 496         buf[2] = bin2bcd(t->time.tm_hour);
 497         buf[3] = bin2bcd(t->time.tm_mday);
 498
 499         /* set ALARM2 to non-garbage */
 500         buf[4] = 0;
 501         buf[5] = 0;
 502         buf[6] = 0;
 503
 504         /* optionally enable ALARM1 */
 505         buf[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE);
 506         if (t->enabled) {
 507                 dev_dbg(dev, "alarm IRQ armed\n");
 508                 buf[7] |= DS1337_BIT_A1IE;      /* only ALARM1 is used */
 509         }
 510         buf[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);
 511
 512         ret = ds1307->write_block_data(client,
 513                         DS1339_REG_ALARM1_SECS, 9, buf);
 514         if (ret < 0) {
 515                 dev_err(dev, "can't set alarm time\n");
 516                 return ret;
 517         }
 518
 519         return 0;
 520 }
 521
 522 static int ds1307_alarm_irq_enable(struct device *dev, unsigned int enabled)
 523 {
 524         struct i2c_client       *client = to_i2c_client(dev);
 525         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 526         int                     ret;
 527
 528         if (!test_bit(HAS_ALARM, &ds1307->flags))
 529                 return -ENOTTY;
 530
 531         ret = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
 532         if (ret < 0)
 533                 return ret;
 534
 535         if (enabled)
 536                 ret |= DS1337_BIT_A1IE;
 537         else
 538                 ret &= ~DS1337_BIT_A1IE;
 539
 540         ret = i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, ret);
 541         if (ret < 0)
 542                 return ret;
 543
 544         return 0;
 545 }
 546
 547 static const struct rtc_class_ops ds13xx_rtc_ops = {
 548         .read_time      = ds1307_get_time,
 549         .set_time       = ds1307_set_time,
 550         .read_alarm     = ds1337_read_alarm,
 551         .set_alarm      = ds1337_set_alarm,
 552         .alarm_irq_enable = ds1307_alarm_irq_enable,
 553 };
 554
 555 /*----------------------------------------------------------------------*/
 556
 557 static ssize_t
 558 ds1307_nvram_read(struct file *filp, struct kobject *kobj,
 559                 struct bin_attribute *attr,
 560                 char *buf, loff_t off, size_t count)
 561 {
 562         struct i2c_client       *client;
 563         struct ds1307           *ds1307;
 564         int                     result;
 565
 566         client = kobj_to_i2c_client(kobj);
 567         ds1307 = i2c_get_clientdata(client);
 568
 569         if (unlikely(off >= ds1307->nvram->size))
 570                 return 0;
 571         if ((off + count) > ds1307->nvram->size)
 572                 count = ds1307->nvram->size - off;
 573         if (unlikely(!count))
 574                 return count;
 575
 576         result = ds1307->read_block_data(client, ds1307->nvram_offset + off,
 577                                                                 count, buf);
 578         if (result < 0)
 579                 dev_err(&client->dev, "%s error %d\n", "nvram read", result);
 580         return result;
 581 }
 582
 583 static ssize_t
 584 ds1307_nvram_write(struct file *filp, struct kobject *kobj,
 585                 struct bin_attribute *attr,
 586                 char *buf, loff_t off, size_t count)
 587 {
 588         struct i2c_client       *client;
 589         struct ds1307           *ds1307;
 590         int                     result;
 591
 592         client = kobj_to_i2c_client(kobj);
 593         ds1307 = i2c_get_clientdata(client);
 594
 595         if (unlikely(off >= ds1307->nvram->size))
 596                 return -EFBIG;
 597         if ((off + count) > ds1307->nvram->size)
 598                 count = ds1307->nvram->size - off;
 599         if (unlikely(!count))
 600                 return count;
 601
 602         result = ds1307->write_block_data(client, ds1307->nvram_offset + off,
 603                                                                 count, buf);
 604         if (result < 0) {
 605                 dev_err(&client->dev, "%s error %d\n", "nvram write", result);
 606                 return result;
 607         }
 608         return count;
 609 }
 610
 611 /*----------------------------------------------------------------------*/
 612
 613 static int ds1307_probe(struct i2c_client *client,
 614                         const struct i2c_device_id *id)
 615 {
 616         struct ds1307           *ds1307;
 617         int                     err = -ENODEV;
 618         int                     tmp;
 619         const struct chip_desc  *chip = &chips[id->driver_data];
 620         struct i2c_adapter      *adapter = to_i2c_adapter(client->dev.parent);
 621         int                     want_irq = false;
 622         unsigned char           *buf;
 623         struct ds1307_platform_data *pdata = client->dev.platform_data;
 624         static const int        bbsqi_bitpos[] = {
 625                 [ds_1337] = 0,
 626                 [ds_1339] = DS1339_BIT_BBSQI,
 627                 [ds_3231] = DS3231_BIT_BBSQW,
 628         };
 629
 630         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)
 631             && !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
 632                 return -EIO;
 633
 634         ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL);
 635         if (!ds1307)
 636                 return -ENOMEM;
 637
 638         i2c_set_clientdata(client, ds1307);
 639
 640         ds1307->client  = client;
 641         ds1307->type    = id->driver_data;
 642
 643         if (pdata && pdata->trickle_charger_setup && chip->trickle_charger_reg)
 644                 i2c_smbus_write_byte_data(client, chip->trickle_charger_reg,
 645                         DS13XX_TRICKLE_CHARGER_MAGIC | pdata->trickle_charger_setup);
 646
 647         buf = ds1307->regs;
 648         if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
 649                 ds1307->read_block_data = i2c_smbus_read_i2c_block_data;
 650                 ds1307->write_block_data = i2c_smbus_write_i2c_block_data;
 651         } else {
 652                 ds1307->read_block_data = ds1307_read_block_data;
 653                 ds1307->write_block_data = ds1307_write_block_data;
 654         }
 655
 656         switch (ds1307->type) {
 657         case ds_1337:
 658         case ds_1339:
 659         case ds_3231:
 660                 /* get registers that the "rtc" read below won't read... */
 661                 tmp = ds1307->read_block_data(ds1307->client,
 662                                 DS1337_REG_CONTROL, 2, buf);
 663                 if (tmp != 2) {
 664                         pr_debug("read error %d\n", tmp);
 665                         err = -EIO;
 666                         goto exit_free;
 667                 }
 668
 669                 /* oscillator off?  turn it on, so clock can tick. */
 670                 if (ds1307->regs[0] & DS1337_BIT_nEOSC)
 671                         ds1307->regs[0] &= ~DS1337_BIT_nEOSC;
 672
 673                 /*
 674                  * Using IRQ?  Disable the square wave and both alarms.
 675                  * For some variants, be sure alarms can trigger when we're
 676                  * running on Vbackup (BBSQI/BBSQW)
 677                  */
 678                 if (ds1307->client->irq > 0 && chip->alarm) {
 679                         INIT_WORK(&ds1307->work, ds1307_work);
 680
 681                         ds1307->regs[0] |= DS1337_BIT_INTCN
 682                                         | bbsqi_bitpos[ds1307->type];
 683                         ds1307->regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
 684
 685                         want_irq = true;
 686                 }
 687
 688                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
 689                                                         ds1307->regs[0]);
 690
 691                 /* oscillator fault?  clear flag, and warn */
 692                 if (ds1307->regs[1] & DS1337_BIT_OSF) {
 693                         i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
 694                                 ds1307->regs[1] & ~DS1337_BIT_OSF);
 695                         dev_warn(&client->dev, "SET TIME!\n");
 696                 }
 697                 break;
 698
 699         case rx_8025:
 700                 tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
 701                                 RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
 702                 if (tmp != 2) {
 703                         pr_debug("read error %d\n", tmp);
 704                         err = -EIO;
 705                         goto exit_free;
 706                 }
 707
 708                 /* oscillator off?  turn it on, so clock can tick. */
 709                 if (!(ds1307->regs[1] & RX8025_BIT_XST)) {
 710                         ds1307->regs[1] |= RX8025_BIT_XST;
 711                         i2c_smbus_write_byte_data(client,
 712                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 713                                                   ds1307->regs[1]);
 714                         dev_warn(&client->dev,
 715                                  "oscillator stop detected - SET TIME!\n");
 716                 }
 717
 718                 if (ds1307->regs[1] & RX8025_BIT_PON) {
 719                         ds1307->regs[1] &= ~RX8025_BIT_PON;
 720                         i2c_smbus_write_byte_data(client,
 721                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 722                                                   ds1307->regs[1]);
 723                         dev_warn(&client->dev, "power-on detected\n");
 724                 }
 725
 726                 if (ds1307->regs[1] & RX8025_BIT_VDET) {
 727                         ds1307->regs[1] &= ~RX8025_BIT_VDET;
 728                         i2c_smbus_write_byte_data(client,
 729                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 730                                                   ds1307->regs[1]);
 731                         dev_warn(&client->dev, "voltage drop detected\n");
 732                 }
 733
 734                 /* make sure we are running in 24hour mode */
 735                 if (!(ds1307->regs[0] & RX8025_BIT_2412)) {
 736                         u8 hour;
 737
 738                         /* switch to 24 hour mode */
 739                         i2c_smbus_write_byte_data(client,
 740                                                   RX8025_REG_CTRL1 << 4 | 0x08,
 741                                                   ds1307->regs[0] |
 742                                                   RX8025_BIT_2412);
 743
 744                         tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
 745                                         RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
 746                         if (tmp != 2) {
 747                                 pr_debug("read error %d\n", tmp);
 748                                 err = -EIO;
 749                                 goto exit_free;
 750                         }
 751
 752                         /* correct hour */
 753                         hour = bcd2bin(ds1307->regs[DS1307_REG_HOUR]);
 754                         if (hour == 12)
 755                                 hour = 0;
 756                         if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
 757                                 hour += 12;
 758
 759                         i2c_smbus_write_byte_data(client,
 760                                                   DS1307_REG_HOUR << 4 | 0x08,
 761                                                   hour);
 762                 }
 763                 break;
 764         case ds_1388:
 765                 ds1307->offset = 1; /* Seconds starts at 1 */
 766                 break;
 767         default:
 768                 break;
 769         }
 770
 771 read_rtc:
 772         /* read RTC registers */
 773         tmp = ds1307->read_block_data(ds1307->client, ds1307->offset, 8, buf);
 774         if (tmp != 8) {
 775                 pr_debug("read error %d\n", tmp);
 776                 err = -EIO;
 777                 goto exit_free;
 778         }
 779
 780         /*
 781          * minimal sanity checking; some chips (like DS1340) don't
 782          * specify the extra bits as must-be-zero, but there are
 783          * still a few values that are clearly out-of-range.
 784          */
 785         tmp = ds1307->regs[DS1307_REG_SECS];
 786         switch (ds1307->type) {
 787         case ds_1307:
 788         case m41t00:
 789                 /* clock halted?  turn it on, so clock can tick. */
 790                 if (tmp & DS1307_BIT_CH) {
 791                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
 792                         dev_warn(&client->dev, "SET TIME!\n");
 793                         goto read_rtc;
 794                 }
 795                 break;
 796         case ds_1338:
 797                 /* clock halted?  turn it on, so clock can tick. */
 798                 if (tmp & DS1307_BIT_CH)
 799                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
 800
 801                 /* oscillator fault?  clear flag, and warn */
 802                 if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
 803                         i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
 804                                         ds1307->regs[DS1307_REG_CONTROL]
 805                                         & ~DS1338_BIT_OSF);
 806                         dev_warn(&client->dev, "SET TIME!\n");
 807                         goto read_rtc;
 808                 }
 809                 break;
 810         case ds_1340:
 811                 /* clock halted?  turn it on, so clock can tick. */
 812                 if (tmp & DS1340_BIT_nEOSC)
 813                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
 814
 815                 tmp = i2c_smbus_read_byte_data(client, DS1340_REG_FLAG);
 816                 if (tmp < 0) {
 817                         pr_debug("read error %d\n", tmp);
 818                         err = -EIO;
 819                         goto exit_free;
 820                 }
 821
 822                 /* oscillator fault?  clear flag, and warn */
 823                 if (tmp & DS1340_BIT_OSF) {
 824                         i2c_smbus_write_byte_data(client, DS1340_REG_FLAG, 0);
 825                         dev_warn(&client->dev, "SET TIME!\n");
 826                 }
 827                 break;
 828         case mcp7941x:
 829                 /* make sure that the backup battery is enabled */
 830                 if (!(ds1307->regs[DS1307_REG_WDAY] & MCP7941X_BIT_VBATEN)) {
 831                         i2c_smbus_write_byte_data(client, DS1307_REG_WDAY,
 832                                         ds1307->regs[DS1307_REG_WDAY]
 833                                         | MCP7941X_BIT_VBATEN);
 834                 }
 835
 836                 /* clock halted?  turn it on, so clock can tick. */
 837                 if (!(tmp & MCP7941X_BIT_ST)) {
 838                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS,
 839                                         MCP7941X_BIT_ST);
 840                         dev_warn(&client->dev, "SET TIME!\n");
 841                         goto read_rtc;
 842                 }
 843
 844                 break;
 845         default:
 846                 break;
 847         }
 848
 849         tmp = ds1307->regs[DS1307_REG_HOUR];
 850         switch (ds1307->type) {
 851         case ds_1340:
 852         case m41t00:
 853                 /*
 854                  * NOTE: ignores century bits; fix before deploying
 855                  * systems that will run through year 2100.
 856                  */
 857                 break;
 858         case rx_8025:
 859                 break;
 860         default:
 861                 if (!(tmp & DS1307_BIT_12HR))
 862                         break;
 863
 864                 /*
 865                  * Be sure we're in 24 hour mode.  Multi-master systems
 866                  * take note...
 867                  */
 868                 tmp = bcd2bin(tmp & 0x1f);
 869                 if (tmp == 12)
 870                         tmp = 0;
 871                 if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
 872                         tmp += 12;
 873                 i2c_smbus_write_byte_data(client,
 874                                 ds1307->offset + DS1307_REG_HOUR,
 875                                 bin2bcd(tmp));
 876         }
 877
 878         ds1307->rtc = rtc_device_register(client->name, &client->dev,
 879                                 &ds13xx_rtc_ops, THIS_MODULE);
 880         if (IS_ERR(ds1307->rtc)) {
 881                 err = PTR_ERR(ds1307->rtc);
 882                 dev_err(&client->dev,
 883                         "unable to register the class device\n");
 884                 goto exit_free;
 885         }
 886
 887         if (want_irq) {
 888                 err = request_irq(client->irq, ds1307_irq, IRQF_SHARED,
 889                           ds1307->rtc->name, client);
 890                 if (err) {
 891                         dev_err(&client->dev,
 892                                 "unable to request IRQ!\n");
 893                         goto exit_irq;
 894                 }
 895
 896                 device_set_wakeup_capable(&client->dev, 1);
 897                 set_bit(HAS_ALARM, &ds1307->flags);
 898                 dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
 899         }
 900
 901         if (chip->nvram_size) {
 902                 ds1307->nvram = kzalloc(sizeof(struct bin_attribute),
 903                                                         GFP_KERNEL);
 904                 if (!ds1307->nvram) {
 905                         err = -ENOMEM;
 906                         goto exit_nvram;
 907                 }
 908                 ds1307->nvram->attr.name = "nvram";
 909                 ds1307->nvram->attr.mode = S_IRUGO | S_IWUSR;
 910                 sysfs_bin_attr_init(ds1307->nvram);
 911                 ds1307->nvram->read = ds1307_nvram_read,
 912                 ds1307->nvram->write = ds1307_nvram_write,
 913                 ds1307->nvram->size = chip->nvram_size;
 914                 ds1307->nvram_offset = chip->nvram_offset;
 915                 err = sysfs_create_bin_file(&client->dev.kobj, ds1307->nvram);
 916                 if (err) {
 917                         kfree(ds1307->nvram);
 918                         goto exit_nvram;
 919                 }
 920                 set_bit(HAS_NVRAM, &ds1307->flags);
 921                 dev_info(&client->dev, "%zu bytes nvram\n", ds1307->nvram->size);
 922         }
 923
 924         return 0;
 925
 926 exit_nvram:
 927 exit_irq:
 928         rtc_device_unregister(ds1307->rtc);
 929 exit_free:
 930         kfree(ds1307);
 931         return err;
 932 }
 933
 934 static int ds1307_remove(struct i2c_client *client)
 935 {
 936         struct ds1307 *ds1307 = i2c_get_clientdata(client);
 937
 938         if (test_and_clear_bit(HAS_ALARM, &ds1307->flags)) {
 939                 free_irq(client->irq, client);
 940                 cancel_work_sync(&ds1307->work);
 941         }
 942
 943         if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags)) {
 944                 sysfs_remove_bin_file(&client->dev.kobj, ds1307->nvram);
 945                 kfree(ds1307->nvram);
 946         }
 947
 948         rtc_device_unregister(ds1307->rtc);
 949         kfree(ds1307);
 950         return 0;
 951 }
 952
 953 static struct i2c_driver ds1307_driver = {
 954         .driver = {
 955                 .name   = "rtc-ds1307",
 956                 .owner  = THIS_MODULE,
 957         },
 958         .probe          = ds1307_probe,
 959         .remove         = ds1307_remove,
 960         .id_table       = ds1307_id,
 961 };
 962
 963 module_i2c_driver(ds1307_driver);
 964
 965 MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
 966 MODULE_LICENSE("GPL");